110：上游超时＆111连接失败-nginx + nodejs（无php-fm，无上游设置）

Question

我有一个第三方服务，可以发布请求。我在新的云计算服务（亚太地区）上进行了此设置。在新服务器上，我无法收到发布请求（通过此服务，我可以使用curl和postman进行发布，这似乎还可以）。我注意到以下错误（尤其是111连接失败，但也定期出现110上游超时）。我遵循了流行的答案here和here。

我应该在我的nginx配置上使用上游吗？

ty！

日志示例：

 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 1xx.xx.xxx.xx, server: mydomain.hk, request: "POST /checkout/someservice/notifyUrl/ HTTP/1.1", upstream: "http://127.0.0.1:3000/checkout/someservice/notifyUrl/", host: "mydomain.hk"

nginx：

server {
        listen 80;
        listen [::]:80;
        server_name mydomain.hk;
        return 301 https://mydomain.hk$request_uri;
}

server {
        # SSL configuration

        listen 443 ssl http2;
        listen [::]:443 ssl http2;

        server_name mydomain.hk;

        ssl_certificate /etc/nginx/my-cert-bundle.crt;
        ssl_certificate_key /etc/nginx/mycertkey.key;

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_prefer_server_ciphers on;
        ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';

         root /var/www/react_app;

        # Add index.php to the list if you are using PHP
        # index index.html index.htm index.nginx-debian.html;

        location / {
                try_files $uri @app;
        }

        location @app {
                root /var/www/express_app;
                proxy_set_header        Host $host;
                proxy_set_header        X-Real-IP $remote_addr;
                proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header        X-Forwarded-Proto $scheme;
                proxy_pass http://127.0.0.1:3000;
            # these two lines here
                proxy_http_version 1.1;
                proxy_set_header Connection "";
     }

        location /shop {
                root /var/www/react_app;
                proxy_set_header        Host $host;
                proxy_set_header        X-Real-IP $remote_addr;
                proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header        X-Forwarded-Proto $scheme;
                index  index.html;
                try_files $uri /index.html;
                proxy_pass http://127.0.0.1:3001;
        }

}